Auto—focus Eyeglasses

With round lenses set in super-thick frames， these new eyeglasses look like they belong on a cartoon character. But what they lack in style， they make up for in （A） s design. Their lenses are made of glycerin （甘油） — a thick， colorless （1） l — encased in clear rubber. And without effort， they will focus on whatever the wearer looks at.

Nazmul Hasan is the first to admit that the （2） g

he helped design may not be comfortable — or look cool. “Theyre not very fashionable and theyre heavy，” he says. Still， these glasses are truly special. The （B） l in normal glasses curve in a specific way to help a persons eyes focus on something close or far away. Not everyone who needs glasses requires the same curvature. So one persons glasses will not necessarily work for someone else. In （3） c ， the glasses that Hasan and his team designed can be adjusted to meet anyones visual needs.

Consider， for example， someone who wants to read a Times story. With an App on her phone， the reader sends her lens prescription to the glasses. Now， when she puts the glasses on， a small infrared light in the （4） f begins sending out light pulses. That light bounces off whats in front of the wearer — here， perhaps your smartphone — and back to the glasses. Those spectacles use the bounced light to calculate the （C） d from the glasses to the smartphone （D） s . Tiny motors in the frame respond by bending the lens so that its curvature matches the persons prescription. Then the article comes into focus.

Tunable， liquid lenses can be turned into “instant prescription eyewear”. One of the advantages is that these tunable glasses could be useful in emergencies and in poor countries. A whole family might use one pair as a backup for broken glasses. Millions of people in developing countries can not afford an eye exam or do not have （5） a to optometrists （驗光师）. Low-cost， self-focusing liquid lenses can become a relatively cheap （E） s

.

（A， B， C， D， E FOR CROSS， 1， 2， 3， 4， 5 FOR DOWN. The first letters of the absents were given.）